1. Field
The following description relates to a cognitive radio communication system, and more particularly, to an apparatus and method of facilitating cooperation in a cognitive radio communication system.
2. Description of Related Art
Much research is currently underway involving technologies that efficiently use limited frequency resources. Cognitive radio technology is in the spotlight.
A cognitive radio communication system using the cognitive radio technology may recycle limited frequency resources to more efficiently use frequency resources. According to the cognitive radio technology, a secondary base station and a secondary terminal that belong to a secondary communication system may periodically or aperiodically sense radio resources used in a primary communication system, recognize an available frequency resource, and transmit and receive data using the recognized available frequency resource.
However, a primary base station and a primary terminal in the primary communication system may have priority with respect to the available frequency band. Accordingly, where a signal of the secondary communication system may collide with a signal of the primary communication system, the secondary base station and the secondary terminal may need to suspend the communication operations or change a frequency resource to another frequency resource.
Attention is also being paid to a multiple input multiple output (MIMO) communication system that performs communications using a plurality of channels. It is possible to achieve a diversity gain by forming a plurality of channels between users and a plurality of antennas of a base station in the MIMO communication system.
Where a secondary communication system using a cognitive radio technology is a MIMO communication system, there is a need to bring together the MIMO communication technology and the cognitive radio technology.